I think what he's getting at (I'm not the one you're responding to) is that something we see in space that appears more fundamental is evidence that we are so f

I think what he's getting at (I'm not the one you're responding to) is that something we see in space that appears more fundamental is evidence that we are so far from understanding that it just looks normal to us. Imagine ants walking on concrete. It is probably indistinguishable from naturally occurring ground to them. They probably don't even realize people make it. We could look up at the sky every day and see something that is evidently made by a civilization, at least to them and others on par with them, and think "that's pretty." We really don't know what sort of activities they'd be up to to even know what is and isn't evidence of their existence, if they were sufficiently advanced.